利用全国 40个地面台站的观测资料对ERA5及ERA5-Land两种不同空间分辨率的再分析资料开展了地面风速误差评估研究,结果表明:ERA5和ERA5-Land资料多年平均风速偏差的平均值分别为 0.08 m s-1、-0.06 m s-1,偏差的最大值分别为 0.46 m s-1、-0.19 m s-1,相对偏差的平均值为 4.4%、-2.0%,相对偏差的最大值分别为33.0%、-10.1%;月平均风速线性拟合方程的斜率分别为0.93、0.97,截距分别为0.29 m s-1、0.02 m s-1,相关系数分别为 0.98、0.99;月平均风速均方根误差的平均值分别为 0.17 m s-1、0.14 m s-1,均方根误差的最大值分别为0.49 m s-1、0.22 m s-1,相对均方根误差的平均值为7.4%、5.7%,相对均方根误差的最大值分别为35.2%、13.3%.ERA5-Land高分辨率资料地面风速误差相对较低,有利于提高风能资源评估的准确性.
Preliminarily Comparative Study on the Applicability of ERA5 and ERA5-Land Ground Wind Speed Data over China's Land Region
Observation data from 40 ground stations in China are used to evaluate the ground wind speed error of ERA5 and ERA5-Land reanalysis data with different resolutions.The results show that the mean bias errors(BEs)of the multiyear mean wind speed of ERA5 and ERA5-Land reanalysis data are 0.08 and-0.06 m s-1,respectively;the maximum BEs are 0.46 and-0.19 m s-1,respectively;the relative BEs(RBEs)are 4.4%and-2.0%,respectively;and the maximum RBEs are 33.0%and-10.1%respectively.Moreover,the slopes of the linear fitting equation of monthly mean wind speed are 0.93 and 0.97,respectively;the intercepts are 0.29 and 0.02 m s-1,respectively;the correlation coefficients are 0.98 and 0.99,respectively;the mean root mean square errors(RMSEs)of the monthly mean wind speed are 0.17 and 0.14 m s-1,respectively;the maximum RMSEs are 0.49 and 0.22 m s-1,respectively;the relative RMSEs(RRMSEs)are 7.4%and 5.7%,respectively;and the maximum RRMSEs are 35.2%and 13.3%,respectively.The above errors in the high-resolution ground wind speed data of ERA5-Land is relatively low,which is conducive to improving the accuracy of wind energy resource assessment.